Friday, February 19, 2010

Coal to Gas, Coal to Hydrogen

Coal represents a massive energy resource to allow a smooth transition from a petroleum economy to a sustainable energy economy. Cleaner and more efficient means of using coal (and other unconventionals like oil sands, oil shale, heavy oil) will be necessary, as unconventional fossil fuels displace light, sweet crude in transportation and other energy uses. The clean gasification of coal is an important process for eliminating much of the pollution from coal combustion that is rampant in China and India at this time.

By adding a catalyst to the coal gasification system, GreatPoint Energy is able to reduce the operating temperature in the gasifier, while directly promoting the reactions that yield methane, (CH4). Under these mild catalytic conditions, less expensive reactor components are required, pipeline grade methane is produced, and very low cost carbon sources (such as lignites, sub-bituminous coals, tar sands, petroleum coke and petroleum resid) can be used as feedstocks.

Because hydromethanation is a catalytic process that does not rely on combustion, it does not produce the nitrogen oxide (NOx), sulphur oxide (SOx) and particulate emissions typically associated with the burning of carbon feedstock. Instead, the process captures nearly all of the impurities found in coal, petroleum coke and biomass and converts them into valuable chemical-grade byproducts.

The first step in the hydromethanation process is to combine the catalyst with the feedstock in such a way as to ensure that the catalyst disperses throughout the matrix of the feedstock for effective reactivity. The catalyst/feedstock material is then loaded into the hydromethanation reactor.

Inside the reactor, pressurized steam is injected to “fluidize” the mixture and ensure constant contact between the catalyst and the carbon particles. In this environment, the catalyst facilitates multiple chemical reactions between the carbon and the steam on the surface of the coal or biomass.

Compared to more conventional approaches to gasification and SNG production, the bluegas process eliminates the need for an external water gas shift reactor, a methanation reactor, and air separation plant.

The hydrogen will be used for industrial applications or combusted to generate near-zero carbon electricity. The SNG can be transported in the existing pipeline infrastructure and used as fuel in home heating, power plants or industrial processes. _GCC

Although hydrogen is an inferior fuel, it is quite useful in chemical processes of various types -- including the production of superior fuels using biomass, coal, and other carbon sources.